The invention relates to fluid-level indicating and control devices which involve magnetically sensitive electric switches at predetermined liquid levels, in conjunction with a float-carried permanent magnet for actuating the switches at particular levels.
In conventional devices of the character indicated, the emphasis has been on integrity of level indication, so that even if there were plural switches in a given array of switches coursed by the float magnet, it has been essential that they be at fixed and ascertained elevations, to assure reliability and accuracy of level indications resulting from switch actuations.
However, there are situations in which it is necessary to periodically adjust the distance between two fluid levels. An example of such a situation is in the control of the "stop-start" operation of a pump motor in a fluid-processing tank. But conventional devices employing float-actuation of magnetic switches do not lend themselves to such adjustment.